The present invention relates to methods for producing chewing gum. More particularly, the invention relates to methods for producing chewing gum containing high-potency sweetener particles which have been coated with zein to enhance shelf-life stability and/or delayed release.
In recent years, efforts have been devoted to controlling the release characteristics of various ingredients in chewing gum. Most notably, attempts have been made to delay the release of sweeteners and flavors in various chewing gum formulations to thereby lengthen the satisfactory chewing time of the gum. Delaying the release of sweeteners and flavors can also avoid an undesirable overpowering burst of sweetness or flavor during the initial chewing period. On the other hand, some ingredients have been treated so as to increase their rate of release in chewing gum.
In addition, other efforts have been directed at protecting high-potency sweeteners within the chewing gum formulation, to thereby increase the shelf-stability of the ingredient, i.e. the protection against degradation of the high-potency sweetener over time.
For example, U.S. Pat. No. 4,597,970 to Sharma et al., teaches a process for producing an agglomerated sweetener wherein the sweetener is dispersed in a hydrophobic matrix consisting essentially of lecithin, a glyceride, and a fatty acid or wax having a melting point between 25.degree. and 100.degree. C. The method disclosed uses a spray congealing step to form the sweetener-containing matrix into droplets followed by a fluid bed second coating on the agglomerated particles.
U.S. Pat. Nos. 4,515,769 and 4,386,106, both to Merrit et al., teach a two step process for preparing a delayed release flavorant for chewing gum. In this process, the flavorant is prepared in an emulsion with a hydrophyllic matrix. The emulsion is dried and ground and the particles are then coated with a water impermeable substance.
U.S. Pat. No. 4,230,687, to Sair et al., teaches a process for encasing an active ingredient to achieve gradual release of the ingredient in a product such as chewing gum. The method described involves adding the ingredient to an encapsulating material in the form of a viscous paste. High shear mixing is used to achieve a homogeneous dispersion of the ingredient within the matrix which is subsequently dried and ground.
U.S. Pat. No. 4,139,639, to Bahoshy et al., teaches a process of "fixing" aspartame by co-drying (by spray drying or fluid bed coating) a solution containing aspartame and an encapsulating agent, such as gum arabic, to thereby surround and protect the aspartame during storage in the gum.
U.S. Pat. No. 4,673,577 to Patel teaches a process wherein high-potency sweeteners are encapsulated with food grade shellac.
U.S. Pat. No. 4,384,004, to Cea et al., teaches a method of encapsulating aspartame with various encapsulating agents, including zein, by various encapsulation techniques, such as spray drying, in order to increase the shelf-stability of the aspartame.
Co-pending U.S. patent application Ser. No. 134,948 filed on Dec. 18, 1987, assigned to the assignee of the present invention, discloses a novel process of applying zein as a second coating to high-potency sweeteners for chewing gum.
Zein is a protein of the prolamine class which is derived from corn. In the past, zein has found many uses as a coating material. For example, the co-pending application reports the surprising result of increased stability of dipeptide sweeteners in aldehyde flavor containing chewing gums when the sweetener particles receive a coating of zein as a second coat.
Unfortunately, a potential disadvantage of using zein as a coating material for high-potency sweeteners in chewing gum is that zein tends to form a relatively hard and crunchy coating. As a consequence, zein coated particles above a certain size can impart a grainy texture, or grittiness, to the chewing gum. Because the zein coating is relatively frangible, any grittiness generally passes quickly as the zein is broken into smaller pieces by chewing. However, even a momentary grittiness in the chewing gum can lead to customer dissatisfaction.
Although much of the problem with grittiness may be overcome by using smaller particles, it is noted that the particle size is important in determining the exact release profile of coated high-potency sweetener. Thus, while the desire to overcome grittiness may dictate the use of smaller zein coated particles, a certain delayed release profile may dictate the use of larger particles.